In the late 50's and continuing into the 70's television experienced a boom in popularity due to the lowered cost of owning a set. The dominating genre on TV at this time was the western. At one point as many as 26 individual shows were classified as westerns. This saturation eventually killed the market and shows were cancelled left and right. The variations of the genre continue to this day and westerns have been resurrected on the big screen winning an Oscar along the way.
SuperHero films like other genres before have been in and out of vogue, especially over the last 20 years or so. It stands to reason that at some point in the not too distant future we will see a time where there won't be 3 or 4 feature films released in a year and also have competing shows on TV networks. We are most likely in the midst of the golden age of superhero films!
Time will have to pass before we can truly assess the quality and impact of the current state of films. In the future fans may find themselves yearning for a film featuring any hero regardless of how many villains he fights, whether or not he/she wears the comics accurate costume or follows the origin/story faithfully. So try to enjoy it while it lasts and not be too nitpicky over choices studios and directors make, if you were given the chance to make such a film your choices may not please everyone either.